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How is salivary gland cancer diagnosed?

Salivary gland cancer is most often diagnosed when a person goes to a doctor because of symptoms he or she is having.

If you have signs or symptoms that might be caused by a salivary gland tumor, your doctor will do exams and tests to find out if it’s cancer or some other condition. If cancer is found, other tests may be done to find out if it has spread.

Medical history and physical exam

Usually the first step is to take your medical history. The doctor will ask about your symptoms and when they first appeared. You might also be asked about possible risk factors for salivary gland cancer and about your general health.

During the physical exam, your doctor will carefully examine your mouth and the areas on the sides of your face and around your ears and jaw, and will feel for enlarged lymph nodes (lumps under the skin) in your neck area, since these could be signs of cancer spread.

The doctor will also check for numbness or weakness in part of your face (which can happen when cancer spreads into nerves) and any other related problem that you may be having.

If the results of this exam are abnormal, your doctor may order imaging tests or refer you to an ear, nose, and throat (ENT) doctor, also known as an otolaryngologist, who will do a more thorough exam of the head and neck area.

Imaging tests

Imaging tests use x-rays, magnetic fields, or radioactive particles to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find a suspicious area that might be cancer, to learn how far cancer may have spread, and to help find out if treatment has been effective.

X-rays

If you have a lump or swelling near your jaw, your doctor may order x-rays of the jaws and teeth to look for a tumor.

If you have been diagnosed with cancer, an x-ray of your chest may be done to see if the cancer has spread to your lungs. This also provides other information about your heart and lungs that might be useful if surgery is planned.

Computed tomography (CT or CAT) scan

A CT scan uses x-rays to produce detailed cross-sectional images of your body. Unlike a regular x-ray, CT scans can show the detail in soft tissues (such as internal organs). A CT scan can show the size, shape, and position of a tumor and can help find enlarged lymph nodes that might contain cancer. If needed, CT scans can also be used to look for tumors in other parts of the body.

Instead of taking one picture, like a regular x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these into images of slices of the part of your body that is being studied.

Before the scan, you may be asked to drink 1 to 2 pints of a liquid called oral contrast. This helps outline the intestine so that certain areas are not mistaken for tumors. This is most often needed for CT scans of the abdomen or pelvis.

You may also receive an IV (intravenous) line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline structures in your body. The injection can cause some flushing (redness and warm feeling). Some people are allergic and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have any allergies or have ever had a reaction to any contrast material used for x-rays.

A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring you have to lie in while the pictures are being taken.

Magnetic resonance imaging (MRI) scan

Like CT scans, MRI scans make detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into very detailed images of parts of the body. A contrast material called gadolinium is often injected into a vein before the scan to better see details.

MRI scans can help determine the exact location and extent of a tumor. Sometimes they can help a doctor tell a benign tumor from a malignant one. They can also help tell if any lymph nodes are enlarged or if other organs have suspicious spots, which might be due to the spread of cancer.

MRI scans take longer than CT scans – often up to an hour – and are a little more uncomfortable. You may have to lie on a table that slides into a narrow tube, which is confining and can upset people who have a fear of enclosed spaces. Newer, more open MRI machines can sometimes be used instead if needed. The MRI machine makes buzzing and clicking noises that you may find disturbing. Some places will provide earplugs or headphones to help block this noise out.

Positron emission tomography (PET) scan

A PET scan looks for areas of high cellular activity (which might be a sign of cancer), rather than just showing if areas look abnormal based on their size or shape. This test can help show whether an abnormal lump or tumor seen on another imaging test may be cancer. If you have been diagnosed with cancer, your doctor may use this test to see if the cancer has spread to lymph nodes or other parts of the body. A PET scan can also be useful if your doctor thinks the cancer might have spread but doesn’t know where.

For this test, you receive an injection of a radioactive substance (usually a type of sugar known as FDG). The amount of radioactivity used is very low and will pass out of the body over the next day or so. Because cancer cells in the body are growing quickly, they absorb more of the radioactive sugar. After about an hour, you are moved onto a table in the PET scanner. You lie on the table for about 30 minutes while a special camera creates a picture of areas of radioactivity in the body. The picture is not finely detailed like a CT or MRI scan, but it can provide helpful information about your whole body.Some machines are able to do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed picture of that area on the CT scan.

Biopsy

Symptoms and the results of exams or imaging tests may strongly suggest you have salivary gland cancer, but the actual diagnosis is made by removing cells from an abnormal area and looking at them under a microscope. This is known as a biopsy. Different types of biopsies might be done, depending on the situation.

Fine needle aspiration (FNA) biopsy

An FNA biopsy is used to remove a small amount of cells and fluid from a lump or tumor for testing. This type of biopsy can be done in a doctor’s office or clinic. It’s done with a thin, hollow needle much like those used for routine blood tests.

Your doctor may first numb the area over the tumor with local anesthesia. The doctor then puts the needle directly into the tumor and pulls cells and a few drops of fluid into a syringe. The sample is then sent to a lab, where it’s checked under a microscope to look for cancer cells.

Doctors may use FNA if they are not sure whether a lump is a salivary gland cancer. The FNA might show the lump is due to an infection, a benign (non-cancerous) salivary tumor, or a salivary gland cancer. In some cases this type of biopsy can help a person avoid unnecessary surgery.

An FNA biopsy is only helpful if enough cells are taken out to be able to tell for certain what a tumor is made of. But sometimes not enough cells are removed, or the biopsy is read as negative (normal) even when the tumor is cancer. If the doctor is not sure about the FNA results, a more extensive type of biopsy might be needed.

Incisional biopsy

This type of biopsy may sometimes be done if the FNA biopsy does not get a large enough sample to examine. In this procedure, the surgeon numbs the area over the tumor, makes a small incision (cut) with a scalpel and takes out a tiny part of the tumor. The specimen is sent to the lab to be looked at by the pathologist. These types of biopsies are not done often for salivary gland tumors.

Surgery

As mentioned above, FNA biopsy of a suspected salivary gland cancer may not always provide a clear answer. If this is the case but the physical exam and imaging tests suggest that cancer may be present, the doctor may advise surgery to remove the tumor completely. This can both provide enough of a sample for a diagnosis and treat the tumor at the same time (see the “Surgery for salivary gland cancer” section for more information).

In some cases if the exams and tests suggest cancer is likely, the doctor may skip the FNA biopsy altogether and go directly to surgery to remove the tumor. The specimen is then sent to the lab to confirm the diagnosis.